1. Field of the Invention
The present invention relates to, in a VCR combined with camera (hereinafter "camcorder") utilizing a loading ring to a locking device of a middle pole for drawing out the tape from a tape cassette so as to form a tape travelling path advancing from the stop mode to the tape loading mode and more particularly, to a middle pole locking device for a camcorder utilizing a loading ring for simplifying the structure, reducing the occupying space, and preventing the fine vibration of middle pole from minimizing so that the travelling of tape is effectively stable.
2. Description of the Prior Art
Several types of devices for preventing the fine vibration of middle pole from minimizing in a camcorder utilizing a loading ring are well known in the art. A conventional device of such devices is illustrated in FIGS. 1A and 1B. As shown in FIGS. 1A and 1B, the conventional device includes a bracket 1 of a plate fixed at one side of a main base (not shown) at a predetermined height, a cam gear 3 having a cam groove 3a at the lower surface thereof, a guide surface 3b in smaller diameter and a protruding guide surface 3c in larger diameter at the upper surface thereof, the cam gear 3 being rotatably mounted on a pivot pin 2 fixed at the side of the bracket I, a gear lever 6 provided with a guide pin 5 to be inserted into the cam groove 3a of the cam gear 3 at the top end thereof and a gear segment 6a in a predetermined circular arc at the other end thereof and a pressing lever 8 and a leaf spring 9 connected with each other by means of a tensional coil spring 7, the gear lever 6 being rotatably mounted on a hinge pin 4 fixed on the upper surface of the bracket 1, a middle arm assembly 11 provided, at one end thereof, with a gear 11a meshed with the gear segment 6a of the gear lever 6 and a middle pole 12 fixed at a middle arm 11a thereof, the middle arm assembly 11 being pivotally mounted on a hinge pivot 13 fixed on the bracket 1, and a guide plate 14 having a hooking groove 14a for supporting the top end of middle pole 12 at a predetermined height being mounted at the upper side of the bracket 1. Also, the device is provided with a guide surface 1a for guiding the bottom end portion of the middle pole 12 and a loading ring 15.
As shown in FIG. 1A, when the cam gear 3 is turned counterclockwise at a predetermined angle by the driving force of a loading motor at a state before loading, the gear lever 6, since the guide pin 5 is inserted into the cam groove 3a of cam gear 3, is turned counterclockwise around the hinge pin 4. Therefore, the middle arm assembly 11 having the gear means 11a meshed with gear segment 6a of the gear lever 6 is turned clockwise around the hinge pivot 13.
Thus, when reaching the time point that the loading operation of tape finishes, the top and the bottom ends of the middle pole 12 are contacted simultaneously to the guide surface 1a of the bracket 1 and the hooking groove 14a of the guide plate 14. When the cam gear 3 is further turned in a predetermined angle as shown in FIG. 1B, the leaf spring 9 is guided on the protruding guide surface 3c of the cam gear 3 so that the leaf spring 9 is turned clockwise around the hinge pin 4. Accordingly, the pressing lever 8 connected by the tensional coil spring 7 with the leaf spring 9 is turned clockwise around the hinge pin 4 by the tensile strength of the tensional coil spring 7 and makes the middle pole 12 to be press-contacted. At this moment, the tensional coil spring 10 for connecting the gear lever 6 with the leaf spring 9 is maintained in a tensioned state by the turning action of the leaf spring 9.
On the other hand, in a state that the unloading is finished as shown in FIG. 1B, when the cam gear 3 is turned clockwise and the leaf spring 9 is released from the protruding guide surface 3c of the cam gear 3, the leaf spring 9 is turned counterclockwise around the hinge pin 4 by the resilient returning force of the tensional coil spring 10 for connecting the gear lever 6 with the leaf spring 9. Accordingly, the pressure contacting force of the tensional coil spring 7 of the pressing lever 8 is released, the cam gear 3 is kept turned clockwise. Accordingly, the gear lever 6 is turned clockwise and the middle arm assembly 11 is turned counterclockwise around the hinge 13, and consequently becoming the unloading state as shown in FIG. 1A.
However, in the middle pole locking device of the conventional camcorder as described in above, there are a number of problems such as for example, the structure is complicated because of various parts such as the cam gear 3 and gear lever 6 of complicated form and the occupying space is larger even in small deck because of the bracket 1 provided at the upper side of a main base with the predetermined distance and also, a separate guide plate 14 at the upper side of the bracket 1 with predetermined distance. Furthermore, there are a number of problems such as, for example, the middle pole 12 is press-contacted by the resilient force of the tensional coil spring 7 so that the traveling tape is vibrated by a slight movement of the middle pole 12 and also, the slant angle and the azimuth angle are distorted so that the travelling operation of the tape becomes unstable. Therefore, the stable picture screen cannot be obtained.